Sky Seal

Sky Seal (天空封印 ; tenkuu fuuin) is a keyword introduced in SD47, possessed only by the Nexus Horus' Sky Temple. The effect is worded as follows:

Sky Seal (Your Turn) When you summon a "Sky"-named Spirit/Ultimate, you can put Soul Core from your Reserve to your Life. This effect can only be used once per turn.

Sky Seal is an alternative method of Seal, and the difference is that Seal always relies on the Spirit that possesses the keyword, Sky Seal can be activated as long a "Sky"-named Spirit/Ultimate is summoned, allowing sealing to be more easily done.